Test opencv dnn module with tensorflow pre-trained model

test_opencv_dnn.py

import cv2
import numpy as np

def test_dnn_module():
    """ Function to test OpenCV DNN module. """
    model = 'removed_dropout_graph.pb'
    net = cv2.dnn.readNet(model)
    img = cv2.imread('F1_R0_A.png')
    imgGray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    imgGray = imgGray.astype(np.uint8)
    blob = cv2.dnn.blobFromImage(imgGray, 1.0, (28,28), swapRB=True, crop=False)
    net.setInput(blob)
    output = net.forward()
    print(output)